Third column: alternative suppliers are suppliers also offering such products while having an ad package. On their own company profile pages, the right column of the table contains their product descriptions instead of alternative suppliers.

A Quiz Question

The zero-point fluctuations (vacuum fluctuations) of the electromagnetic field

(a) are associated with a certain small density of photons (one photon per mode), which cannot be further reduced because quantum mechanics predicts some balance of absorption and emission processes for any absorber material

(b) are occurring when no photons at all are present

After selecting your answer(s) and pressing this button, find the explanations on the left side.